Air admittance vent

ABSTRACT

An air admittance vent including a housing having a base and a cap with a diaphragm assembly disposed therein. The assembly comprises a diaphragm base, an annular retainer ring, and an annular malleable washer. The diaphragm base has an annular portion and a stem extending orthogonally from the center of the annular portion. The annular retainer ring includes a circumferential skirt engaged with an outer perimeter of the annular portion of the base, with the stem extending beyond the annular retainer ring. The annular malleable washer is disposed between the annular retainer ring and the annular portion of the base. A member extends from the housing base into engagement with the stem for guiding movement of the diaphragm assembly to open or close an ambient air passage through said housing base.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No. 11/039,502 filed Jan. 18, 2005 by the same inventor and assigned to the same assignee.

FIELD OF THE INVENTION

The field of the present invention is pressure equalization mechanisms for plumbing, disposal, and waste systems.

BACKGROUND OF THE INVENTION

The plumbing, disposal, and waste system (PDWS) of most residential and commercial buildings, such as those associated with sinks, bathtubs, and toilets, require mechanisms to equalize pressure between the PDWS and the ambient atmosphere when the pressure in the PDWS is less than atmospheric pressure. Pressure equalization is necessary to maintain the liquid trap seal employed in the most common PDWS.

Traditionally, external ventilation stacks have been used to vent the PDWS to building exteriors, thereby allowing the pressure within a PDWS to constantly equalize to atmospheric pressure. More recently, air admittance vents (AAV) have replaced ventilation stacks. AAVs allow air to enter the PDWS and restrict air from flowing out of the PDWS. By restricting flow (which may include air, gases, and liquid waste) out of the PDWS, an AAV may be placed most anywhere within a building while still preventing negative pressure, i.e., less than atmospheric pressure, to build up within the PDWS.

In order to achieve the desired functionality, an AAV requires a valve that can be responsive to small drops in pressure (less than 1/100 PSI) below atmospheric pressure. The valve also needs to be able to create a good seal in response to small increases in pressure within PDWS being regulated. Finally, the preferred AAV will have a wide range of operating temperatures and will be inert to chemicals that are commonly found in a PDWS, most especially methane gas and water vapor.

SUMMARY OF THE INVENTION

The present invention is directed toward an air admittance vent which includes a housing having a diaphragm assembly disposed therein. The diaphragm assembly chiefly comprises a base, an annular retainer ring, and an annular malleable washer. The base has an annular portion and a stem extending orthogonally from the center of the orthogonal portion. The annular retainer ring engages the annular portion of the base. The annular malleable washer is disposed between the annular retainer ring and the annular portion of the base.

In a first separate aspect of the present invention, the annular retainer ring includes a circumferential skirt which engages the base about the outer perimeter of the annular portion. The circumferential skirt may include a raised lip, and the outer perimeter of the annular portion may include a beveled edge to engage the raised lip of the circumferential skirt.

In a second separate aspect of the present invention, the annular portion of the base includes a first circumferential ridge and the side of the annular retainer ring facing the annular portion includes a second circumferential ridge. Optionally, the first and second circumferential ridges have different radii.

In a third separate aspect of the present invention, the annular portion of the base includes a stepped surface. This stepped surface may include two or more steps. In the two step configuration, the outer step is disposed nearer to the annular retainer ring than the inner step.

In a fourth separate aspect of the present invention, the stem cooperates with a guide member extending from the housing to guide movement of the diaphragm assembly.

In a fifth separate aspect of the present invention, any of the foregoing aspects may be employed in combination.

Accordingly, the present invention provides an improved air admittance valve. Other objects and advantages will appear hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like reference numerals refer to similar components:

FIG. 1 is an exploded view of an air admittance vent diaphragm assembly;

FIG. 2 is a cross-sectional view of an annular retainer ring for the diaphragm assembly of FIG. 1;

FIG. 3 is a cross-sectional view of a base for the diaphragm assembly of FIG. 1;

FIG. 4 is a lateral cross-sectional view of the base stem for the diaphragm assembly of FIG. 1;

FIG. 5 is a cross-sectional view of the air admittance vent diaphragm assembly of FIG. 1;

FIG. 6 is a cross-sectional view of an air admittance vent with the diaphragm assembly shown in the open position;

FIG. 7 is a cross-sectional view of an air admittance vent with the diaphragm assembly shown in the closed position;

FIG. 8 is an exploded view of an alternative embodiment of an air admittance vent diaphragm assembly;

FIG. 9 is a perspective view of the housing for the air admittance vent wherein FIGS. 9A and 9B are the cap and FIGS. 9C and 9D are the housing base;

FIG. 10 is an exploded view of the housing and the alternative diaphragm assembly in both exploded view and assembled;

FIG. 11 is a cross-sectional schematic view showing the air admittance vent with the alternative diaphragm assembly in an open position; and

FIG. 12 shows the structure of FIG. 11 in closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning in detail to the drawings, FIG. 1 illustrates an exploded view of an air admittance vent diaphragm assembly 10. The diaphragm assembly 10 has three primary components: a base 12, an annular malleable washer 14, and an annular retainer ring 16. The annular retainer ring 16 is placed over the base with the annular washer disposed between the base 12 and the annular retainer ring 16. The annular retainer ring 16 is in a snap-fitting engagement with the base 12. The stem 18 extends through the center of the annular washer 14 and the annular retainer ring 16.

The annular washer 14 provides the sealing surface for the diaphragm assembly 10 and is preferably constructed from a malleable neoprene or silicone material. Other materials, however, may also be used. In choosing an appropriate material, flexibility and inertness to certain chemicals, particularly methane gas and water vapor, should be considered. Similarly, the base and the annular retainer ring are constructed from materials chosen to be inert to such chemicals. The base is preferably made out of a hard shore ABS material and the annular retainer ring is preferably constructed from polyethylene or ABS, although other materials may also be used.

Referring to FIG. 2, the annular retainer ring 16 includes an annular portion 20 and a circumferential skirt 22. One end of the circumferential skirt 22 includes a raised lip 24 which is employed to create the snap-fit with the base as described below. The side of the annular portion 20 facing the base, when the base and the annular retainer ring 16 are engaged, includes a circumferential notch 26 and a circumferential ridge 28. The circumferential notch 26 is positioned to receive a complementary rim on the perimeter of the base. The circumferential ridge 28 is positioned to engage and apply pressure to the annular washer 14 when the diaphragm assembly is assembled.

The base 12 of the diaphragm assembly, illustrated in FIG. 3, includes the stem 18 extending orthogonally from the center of an annular portion 30. The annular portion 30 includes a stepped surface 32 and a raised circumferential rim 34 around the stepped surface 32. The side wall 42 of the base 12 generally defines the outer perimeter of the annular portion 30. This side wall 42 includes a beveled edge 44 which is positioned to mutually engage the lip (24 in FIG. 2) of the annular retainer ring. The stepped surface 32 includes an inner step 36 and an outer step 38. A circumferential ridge 40 is disposed around the outer step 38. This circumferential ridge 40 is positioned to engage and apply pressure to the annular washer when the diaphragm assembly is assembled.

A lateral cross section of the stem 18 is illustrated in FIG. 4. The stem 18 has a central core 50 and four legs 52 extending therefrom, with a pair of legs 52 lying along each orthogonal axis, thus providing the stem 18 with a cross section that is substantially X-shaped. The dotted line 54 circumscribed about the cross section of the stem illustrates the overall circumference of the stem 18 and generally represents the air admittance vent opening into which the stem is inserted during use of the diaphragm assembly. The X-shaped form of the stem 18 provides additional volume through which air may flow, thus providing increased air flow through the vent opening when the diaphragm assembly is in use. Furthermore, the X-shaped cross section of the stem 18 allows the effective circumference of the stem 18 to be maximized within the air admittance vent opening to limit lateral movement of the diaphragm assembly and help create a consistent seal during use.

Referring to FIG. 5, which is a cross-sectional view of the full diaphragm assembly, the raised lip 24 on the circumferential skirt 22 is shown engaging the beveled edge 44 of the base 12. This configuration permits the annular retainer ring 16 to have a snap fit with the base 12 and disposes of the need for any glues or adhesives.

The annular washer 14 is engaged with and deformed by the circumferential ridges 28, 40 of the annular retainer ring 16 and the base 12, respectively. The annular washer 14 extends from approximately the circumferential rim 34 to near the stem 18. Note that in the figures the size of the two circumferential ridges 28, 40 is exaggerated for illustration purposes. As a result, actual deformation of the washer is not illustrated in FIG. 5. In practice, each circumferential ridge is proportioned to achieve a seal as described above, such being largely a matter of design choice. The two circumferential ridges 28, 40 preferably have different radii, the difference of which may be as little as 2/1,000 of an inch. The difference in the radii of the two circumferential ridges 28, 40 is generally a matter of design choice, which may be informed by the materials used for and the overall thickness of the annular washer 14. The deformation of the washer by the circumferential ridges 28, 40 provides an airtight seal between the three components of the diaphragm assembly 10.

When assembled, the inner step 36 of the base 12 is further away from the annular retainer ring 16 than is the outer step 38. The space 46 formed between the inner step 36 and the annular washer 14 permits the washer to have a limited amount of movement toward the base 12. The central opening 48 of the annular retainer ring 16 also permits the washer 14 to have limited movement outward away from the base 12. Thus, the washer 14 is provided with limited, bi-directional movement in the longitudinal direction.

Referring to FIGS. 6 & 7, a diaphragm assembly 10 is schematically shown as part of an air admittance vent 60. The air admittance vent includes a cap 62 and a base 64. The base 64 connects to the PDWS (not shown) and includes a channel or passage 66 through which ambient air is allowed to enter the PDWS. The diaphragm assembly 10 rests on the base 64 with the stem 18 in the air admittance vent opening 68.

In FIG. 6, the diaphragm assembly 10 is shown in the open position, while in FIG. 7 the diaphragm assembly 10 is shown in the closed position. When in the open position, the diaphragm assembly 10 allows ambient air to enter through the channel 66 and into the PDWS. This occurs when the pressure in the PDWS is less than the pressure in the ambient atmosphere. The diaphragm assembly 10 is caused to be in the closed position when the pressure in the PDWS is greater than the ambient atmospheric pressure. Under such circumstances, the stem 18 is forced down into the air admittance vent opening 68, and the annular washer (14 of FIG. 5) forms a seal with the rim of the air admittance vent opening 68, thus preventing gases and fluids in the PDWS from escaping into the ambient atmosphere around the air admittance vent.

Referring now more particularly to FIG. 8, there is illustrated an alternative embodiment of the diaphragm assembly constructed in accordance with the principles of the present invention. The diaphragm assembly shown in FIG. 8 is similar to that illustrated in FIG. 1 in that it includes a diaphragm base 70 an annular malleable washer 72 and an annular retaining ring 74. The annular retaining ring 74 snaps into place around the diaphragm base 70 thereby sandwiching the annular malleable washer 72 there between to effect a seal as above-described in conjunction with FIG. 1. The primary difference between the structure shown in FIG. 1 and the structure shown in FIG. 8 is the structure of the stem 76. As is illustrated in FIG. 8, the stem 76 is cylindrical and has a hollow opening 78 defined therein. The stem 76 extends orthogonally from the diaphragm base 70, and as will be described more fully herein below is utilized with a member or pin extending from the housing base to guide the diaphragm assembly in a longitudinal direction between open and closed positions and to maintain the diaphragm assembly in a position such that a secure and positive seal is effected when the valve is in its closed position. It should be recognized by those skilled in the art that the stem 76 although shown as being hollow in FIG. 8 may be solid with the guide member extending from the housing being configured as a hollow member. The construction of the stem and the guide pin allow the diaphragm assembly to move up and down uniformly in the air flow passageway with little or no lateral movement. This structure also results in significant increase in air flow through the air flow passageway.

Referring now more specifically to FIG. 9, the housing for the air admittance valve is illustrated. As is therein shown the cap 80 is hat shaped in configuration and includes internally thereof a plurality of rims 82-92 which fit against a shoulder 94 formed on the housing base 96 to act as a positive stop to the downward travel of the cap 80 when it is fitted over the top of the housing base 96. The housing base as shown in FIGS. 9C and 9D includes an upstanding rim 98 defining an ambient air opening 100 there through, which passes into a central opening 102. A cross-member 104, defines the upper portion of the ambient air opening 100 and extending upwardly therefrom is a guide pin 106. A cross-member 108 defines the lower section of the air admittance passageway. The guide pin 106 cooperates with the stem 76 on the diaphragm assembly to permit controlled movement of the diaphragm assembly between its open and closed positions as may be required in response to a differential pressure between ambient and the PDWS. As indicated above the guide pin 106 may be a solid cylindrical member which fits within the hollow opening shown on the stem in FIG. 8, or alternatively may itself define a hollow opening with the stem 76 being solid and being received within the hollow opening for purposes of properly guiding the movement of the diaphragm assembly.

By reference to FIG. 10, there is illustrated an exploded view the housing base 86 and the housing cap 80 positioned thereon. A diaphragm assembly as illustrated in FIG. 8 is schematically shown in FIG. 10, also in exploded view at 10A and the diaphragm assembly at 10B is shown in its assembled position. The diaphragm assembly in FIG. 10B is shown in position with the stem 76 positioned over the pin 106, which extends upwardly from the base 102. It should be recognized by those skilled in the art that the illustration of FIG. 10 is purely schematic, and reference is made to FIG. 8 for a more precise representation of the details of the alternative embodiment of the diaphragm assembly. From a consideration of the schematic representation shown in FIG. 10, it will be recognized by those skilled in the art that the structure of the guide pin 106 and the stem 76 may be reversed. That is the stem 76 may be constructed of a solid member with the guide pin 106 being hollow, so as to receive the solid stem 76 for operational purposes.

By reference to FIGS. 11 and 12, it will be recognized that they are similar to FIGS. 6 and 7, but illustrate the alternative embodiment in schematic form of the diaphragm assembly with FIG. 11 showing the diaphragm assembly in its open position, so that ambient air can move from ambient through the valve and into PDWS. Such occurs, when the pressure within the PDWS is lower than ambient. In FIG. 12, the valve is shown in its closed position, which occurs when the pressure within the PDWS is higher than ambient.

Thus, an air admittance vent assembly is disclosed. While embodiments of this invention have been shown and described, it will be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the following claims. 

1. An air admittance vent for a plumbing, disposal and waste system (PDWS) comprising: (1) A housing having a cap and a housing base, said housing base defining an ambient air passage therethrough; (2) A diaphragm assembly disposed within said housing and adapted to open and close said ambient air passage responsive to differential pressures between said PDWS and ambient, said diaphragm assembly comprising: (a) A diaphragm base having an annular portion and a stem extending orthogonally from a center of the annular portion; (b) An annular retainer ring having a circumferential skirt, wherein the circumferential skirt engages the base about an outer perimeter of the annular portion and the stem extends beyond the annular retainer ring; and (c) An annular malleable washer disposed between the annular retainer ring and the annular portion of the diaphragm base; and (3) Means extending from said housing base and engaging said stem for guiding movement of said diaphragm assembly between its open and closed positions.
 2. An air admittance vent of claim 1, wherein one of said stem and said means extending from said housing base defines a hollow opening and the other is a pin received within said hollow opening.
 3. An air admittance vent of claim 2, wherein said stem is hollow and said means extending from said housing is a pin.
 4. An air admittance vent of claim 3, wherein the diaphragm base and the annular retainer ring, in combination, include means for the outer perimeter of the annular portion and the circumferential skirt of the annular retainer ring to mutually engage.
 5. An air admittance vent of claim 4, wherein the diaphragm base and the annular retainer ring, in combination, include means for providing an airtight seal between the diaphragm base, the annular retainer ring, and the annular malleable washer. 